Combined volume control and switch



Feb. 15, 1944. H. A. WILLIAMS ET AL COMBINED VOLUME CONTROL AND SWITCHFiled July 15, 1942 INVENTORS.

4 T TOP/V1575.

Patented Feb. 15, 1944 COMBINED VOLUME CONTROL AND SWITCH Hiram A.Williams and Henry A. Baumer, St.

Marys, Pa., assignors to Stackpole Carbon Company, St. Marys, Pa., acorporation of Pennsylvania Application July 13, 1942, Serial No.450,682

10 Claims.

This invention relates to electrical units for radios, and moreparticularly to a combined vol.- ume control and snap switch.

It is now common practice to switch a radio on and off by turning thesame shaft that controls the volume of the radio. For this purpose thecontact arm or control head of the volume control carries a member thatat a certain point in the rotation of the contact arm engages andactuates a trigger by which the snap switch is turned on and ofi. Such acombined unit is shown in I-Iathorn Patent No. 2,127,686. However, thereare still many cases in which the switch and volume control are separateunits and are separately controlled. The usual combined unit is notfavored for replacing only a volume control when the switch is aseparate unit, because even though the switch of the combined unit isnot wired into the circuit it still snaps on and off when the volumecontrol is turned. Where spare parts are carried for replacementpurposes this situation makes it necessary to carry both combined unitsand separate units in order to repair both types of radio sets.

It is among the objects of this invention to provide a combined volumecontrol and snap switch which is suitable for replacing either similarunits or separate volume control units, which does not requiremanipulating the switch of the combined unit when only the volumecontrol is in circuit, which can be quickly converted for use as areplacement for either type of unit, and in which the conversion meansis simple but effective.

In accordance with this invention a snap switch is mounted on thehousing of a volume control in the usual manner with the switch triggerprojecting through an opening into the control housing. This housingencloses the resistance element and electric contact member slidablyengaging the element over which the contact member is moved by amanually rotatable control shaft. Means, such as a'projection, iscarried by the contact member for operatively engaging the switchtrigger at one end of the path of travel of the contact member. Thisprojection actuates the trigger to turn the switch on and 01f when thecontrol shaft is turned. The projection has transient engagement withthe trigger by which is meant that after it turns on the switch it movesaway from the trigger. Means is provided for limiting the movement ofthe trigger-actuating projection to keep it from actuating the switch.This step means may be a lug fastened to the side wall of the volumecontrol housing and projecting into the path of movement of a projectioncarried by the rotatable contact member or it may be a screw or tongueprojecting inwardly from the control housing. The stop means is solocated that it stops the movement of the contact member andtrigger-actuating projection before the latter can move the trigger. Theunit as thus constructed is intended for replacement of volume controlsonly, in cases where the switch is a separate unit. In case the unit isto replace a similar combined unit the stop lug or screw is removed fromthe housing, or the tongue is not bent into operative position, so thatthe trigger-actuating projection can engage the trigger and turn theswitch on and off in the same way as has been customary with these unitsheretofore.

The invention is illustrated in the accompanying drawing in which Fig. 1is an enlarged side view of one of my units with the switch and controlhousings partly broken away; Fig. 2 is a horizontal section taken on theline 11-11 of Fig. l and showing the stop lug in operative position;Fig. 3 is a view similar to Fig. 2 with the stop lug removed fromoperative position so that the switch is turned oif; Fig. 4 is a sideview of the combined unit rotated 90 from that of Fig. 1 and showing amodified embodiment of the invention; Fig. 5 is a fragmentary vie.similar to Fig. 2, of the modification of Fig. 4 with the tongue inoperative position; and Fig. 6 is a frag mentary view, similar to Fig.2, showing a removable screw stop.

Referring to the drawing, an insulating base I is provided with acentral opening fromthe bottom. of which a threaded bushing 2 projects.Extending through this bushing and rotatably mounted therein is acontrol shaft 3 provided. at its outer end with a socket Mounted on thebase member is an electrical resistance element 5 encircling the controlshaft and spaced therefrom. On the inner end of the shaft there arectangular insulating member 6 provided in its opposite ends withnotches l. The bottom of this member is engaged by the body of a metalcontact member having upturned lugs 8 that project into the notches sothat the contact member will be turned by member 6. The central portionof the contact member is spaced from the control shaft. Projectingtoward each other from the ends of the contact member body is a pair ofspring contact fingers 8 having downturned ends that engage and slideupon the resistance element. Terminal members Iii are connected to theopposite ends of the resistance element while an intermedial terminalmember H is electrically connected to the contact member, preferably bymeans of a resilient wire l2 (Fig. 1) coiled around the control shaftbeneath the contact member to which it is attached. This gives apositive electrical connection regardless of the position of the contactmember.

The insulating member 8 is rigidly connected to the control shaft, andthe rotation of the contact member is limited, through the medium of arigid arm l6 tightly clamped against member 6 by the upset inner end ofthe shaft. At one side of member 6 this arm has a pair of laterallyspaced upturned ears I! that engage one side or a the other of a detentis pressed in from the side of the metal control housing is to limit therotathat projection l9 has transient engagement with it.

The combined unit as described thus far is of,

conventional form and operates in a well-known manner when the controlshaft is turned. To permit diiferent types of knobs to be used with thisunit the socket 4 is provided into which any standard control shaft 26,having any desired type of knob-attaching end, can be inserted. Theinner diameter is the same as the outer diameter of shaft 26, so a tightfriction fit is assured. Assembly of the two parts of the control shaftis facilitated and the friction grip is increased by providing thesocket wall with a longitudinal slot 21.. As an added precaution or asan alternative toia friction fit, a small set screw 28 may be threadedin the socket wall with its inner end bearing against shaft 26.

It is a feature of this invention that means is provided for preventingthe switch from being actuated, so that the unit will operate like avolume control without a switch. Accordingly, a small rectangularopening 3| (Fig. 3) is punched in the side wall of the volume controlhousing l9 near detent l8 and a tongue-like metal lug 32 (Fig, 2) ismounted in this opening. The lower end of the lug is spot welded to theoutside of the control housing below opening 3!. The upper portion ofthe lug extends through this opening and projects into the path ofmovement of one of the ears I! on arm l6 and thus limits or stops, themovement of the contact member and of the related parts that rotate withit as they are moving toward switch-opening position. The position ofthe lug relative to stop detent I8 is such that it stops theswitch-actuating projection just as it reaches the switch trigger butbefore it can move the trigger. Therefore, the switch remains in eitheroff or on position, de pending on which side of detent I8 the lug islocated, regardless of the position of the contact member, and in so faras operation is concerned the switch might just as well be absent. Thecontrol shaft thus turns smoothly from one end to the other of its pathof rotation.

In case this unit is used for replacing a similar combined unit so thatit is necessary to use the. switch for its intended purpose as a circuitbreaker, the lug 32 is mounted so that it can be removed from inside thehousing. For this purpose the portion of the lug inside of the controlhousing is doubled back on itself with the upper endextending back outthrough opening 3|. To render the lug inoperative its projecting upperend is gripped by pliers and pulled until either the lug is out of theway of projection I! or is entirely outside of the housing. If desiredthe lug can be twisted off the casing and discarded. As the movement ofthe contact member and switch-actuating projection 20 is no longerrestrained by the lug, the projection 20 can travel far enough to snapthe trigger. The unit is then the same in construction and operation asthe conventional combined volume control and switch.

' A modification is illustrated in Figs. 4 and 5 which uses a stop'member that normally is in inoperative position, unlike lug 32. In thisembodiment the side wall of the volume control housing 36 is cut throughto provide a small tongue 37 attached at its lower end to the housing.The tongue is left in its original position (Fig. 4) as a part of thehousing wall if the switch is to be operated. In case the unit is usedto replace only a volume control so that the operation of the switch isnot desired, tongue 3'! is pushed inwardly by any suitable instrumentinto the path of one of the ears [1, as shown in Fig. 5, care beingtaken that the ear is on the right side of the tongue at the time it ispushed in. Otherwise, the tongue might lock arm l6 against rotation.

In the further modification shown in Fig. 6 the volume control housing4| is provided in its side wall with a circular opening in which a screw42 is threaded. The screw is long enough to project into the path ofprojection IT on control arm "5 and thus prevent the switch from beingoperated. If operation of the switch is desired, the screw can beremoved.

According to the provisions of the patent statutes, we have explainedthe construction and operation of our invention and have illustrated anddescribed what we now consider to represent its best embodiment.However, we desire to have it understood that, within the scope of theappended olaims, the invention may be practiced otherwise than asspecifically illustrated and described. r

We claim:

1. In a combined volume control and snap switch, the combination with aresistance element, an electric-contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and ofi, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a circularhousing for the volumecontrol, of means attached to the side wall of thehousing for limiting the movement of the trigger-actuating means to keepit from operating the switch, said limiting means being manually movableradially of the housing whereby to render the switch operable orinoperable as desired.

2. In a combined volume control and snapswitch, the combination with aresistance element, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and ofi, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the volume control provided with an opening, of a tongue-like stopmember adapted to extend inwardly from said housing opening for intercepting said trigger-actuating means tokeep it from operating theswitch, said stop member being manually movable in a directiontransverse to the path of movement of said trigger-actuating meanswhereby to render the switch operable or inoperable as desired.

3. In a combined volume control and snap switch, the combination with aresistance ele ment, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the volume control provided with an opening, of a tongue-like lugattached to said housing and projecting into the path of movement ofsaid trigger-actuating means to stop the latter before the switch can beoperated, said lug having a portion projecting out of said opening forpulling the lug out to permit the trigger-actuating means to move farenough to operate said trigger.

4. In a combined volume control and snap witch, the combination with aresistance element, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means car ried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the contact member, of a projecting member carried by said contactmember, and means permanently attached to the housing and projectinginto the path of movement of said projecting member for inter cepting itbefore said trigger-actuating means can operate the switch, saidintercepting means being manually movable in a direction transverse tosaid path whereby to render the switch operable or inoperable asdesired.

5. In a combined volume control and snap switch, the combination with aresistance element, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it. and a housingfor the volume control provided with an opening, of a lug attached tosaid housing and projecting into the path of movement of saidtrigger-actuating means for intercepting it before it can operate theswitch, said lug being doubled back upon itself to provide an endportion extending out through said opening, said end portion beingadapted to be pulled to remove the lug from said path whereby the triger-actuating means can operate the trigger.

6. In a combined volume control and snap switch, the combination with aresistance element, an electric contact member engaging said element,manually operable means for movin said member along said element, a snapswitchmounted adjacent said contact member, a trig er for snapping theswitch on and off, means carried by the contact member adapted to havetransient engagement with the trigger to actuate it, a projecting membercarried by the contact member. and stop means adapted to be engaged bysaid projecting member for limiting the extent of movement of saidcontact member after the switch has been actuated, of bendable meanspro- ,iecting into the path of movement of said projecting member forintercepting it before it reaches said stop means and before saidtriggeractuating means can operate th switch, said intercepting meansbeing manually bendable transversely of said path whereby to render theswitch operable or inoperable as desired.

7. In a combined volume control and snap switch, th combination with aresistance element, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the volume control provided with an opening in its side wall, of aseparate lug attached to the outside of the wall of said housing andprojecting through said opening into the path of movement of saidtrigger-actuating means for intercepting it before it can operate theswitch, said lug being doubled back upon itself to provide an endportion extending out through said opening, said end portion beingadapted to be pulled to Pull the lug out through said opening.

8. In a combined volume control and snap switch, the combination with acircular resistance element, a rotatable electric contact memberengaging said element, a control shaft operably connected to the contactmember for rotating it, a snap switch mounted adjacent said contactmember, a trigger for snapping the switch on and off, and atrigger-actuating member carried by the contact member and projectinglaterally from its axis of rotation for transient engagement with thetrigger, of a projecting member carried by said contact member andprojecting laterally from its axis of rotation, and a stop membernormally projecting into the path of movement of said projecting memberfor intercepting it before said trigger-actuating member can operate theswitch, said stop member being bendable to remove it from said pathwhereby to render the switch operable.

9. In a combined volume control and snap switch, the combination with aresistance element, an electric contact member engaging said element,manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the volume control, of a detent formed from the wall of said housingand adapted to be projected inwardly into the path of movement of saidtrigger-actuating means to stop the latter before the switch can beoperated.

10. In a combined volume control and snap switch, the combination with aresistance elemerit. an electric contact member engaging said element.manually operable means for moving said member along said element, asnap switch mounted adjacent said contact member, a trigger for snappingthe switch on and off, means carried by the contact member adapted tohave transient engagement with the trigger to actuate it, and a housingfor the volume control. of a tongue out in the wall of said housing andnormally remaining in its original position as a part of said wall, saidtongue being bendable inwardly int th path of movement of saidtrigger-actuating means to stop the latter before the switch can beoperated.

I-HRAM A. WILLIAMS HENRY A. BAUlLR.

